Should Iressa Come Back in the US? The Argument that Convinced Me
One of my good friends in the lung cancer community, Dr. Ed Kim from MD Anderson, was in town tonight and gave a talk that I attended.
One of my good friends in the lung cancer community, Dr. Ed Kim from MD Anderson, was in town tonight and gave a talk that I attended.
At the recent Chicago lung cancer meeting, the idea of maintenance therapy emerged as a hot topic that is experiencing ongoing changes in our treatment approaches over time. The controversies about this topic begin with the very terminology. Here are four proposed names for the same basic idea:
1) maintenance therapy, which implies that one of the initial treatments is being continued on a longitudinal basis
My kids are right in the middle of that time when they watch SpongeBob and see commercials for toys, cereals, and music, nearly every one is puncuated at the end with, "Daddy, can we get that? I want that." There comes a time in everyone's life, hopefully early on, when we learn that we won't actually find eternal bliss with every advertised item.
As a general rule, companies don't sit on great news with their drugs. Without any insider knowledge, this was my concern about why we hadn't heard anything about the results of three major lung cancer trials with the agent Zactima (vandetanib), which I had written a post about 8 months ago (see prior post about these trials with Zactima, an oral agent that inhibits both VEGF, a major mediator of angiogenesis, and the EGFR pathway).
Well, it happened again that the first word came from the financial community (report here), as we learned today that a large trial testing the value of maintenance tarceva (erlotinib), the oral EGFR inhibitor, provides a significant improvement in progression-free survival (PFS). In the following slide, I show the design for two similar trials that test the value of tarceva after four cycles of first line treatment of advanced NSCLC.
I just recently wrote a post (here) that describes how I became convinced that under certain circumstances there could be a genuine value in determining whether a particular lung cancer patient has a tumor with an EGFR activating mutation.
Most of what I write about here highlights the evidence supporting treatments, and that’s certainly how we strive to practice oncology. But the reality is that patients and doctors often find themselves in the middle of settings where we don’t have any answers and need to rely on judgment, or we think we can potentially do better by defying conventional wisdom. Doctors lie all along the spectrum of being “data-driven” on one end and being a “cowboy” on the other end.
Probably the most contentious areas of lung cancer management is stage IIIA NSCLC, with N2 nodal involvement, the nodes outside of the lungs, toward the middle of the chest but on the same side as the main tumor. One of the key issues is that the staging is the same whether there's a single microscopically involved lymph node or multiple enlarged lymph nodes in a few areas of the mediastinum (mid-chest, between the lungs). But the outcomes of these groups of patients is very different, so it may be worth thinking about them a little differently.
Though EGFR inhibitors like tarceva can produce some terrific and long-lasting results in many patients, they aren't toxicity-free. The "targeted therapies" we use just have a very different side effect profile from standard chemo, and the EGFR inhibitors are well known to have skin-related side effects as the leading problem, with loose stools/diarrhea as a less nearly ubiquitous second place issue.
An interesting trial presented at ASCO 2008 came out of Japan, asking the question of whether there is an advantage to continuing first line platinum-based doublet chemo for up to six cycles or whether it might be better to give just three cycles and then switch from chemo right to the EGFR inhibitor iressa in Japanese patients with advanced NSCLC (abstract here).
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